RICHMOND — It”s just after lunchtime, and the temperature inside the classroom is warm. But more than 20 third-graders sit perfectly still with their arms stretched out over their desks and their eyes closed.

They”re practicing “starfish breathing,” as mindfulness instructor Alison Espinosa leads them through a series of meditation exercises, asking them to trace a feeling of warmth and love through their body and then share it with the world. Then the group breaks out in a song.

Many adults would be hard-pressed to explain what exactly mindfulness means or know how to call on it during times of stress. But for thousands of students at the West Contra Costa Unified School District, it”s a weekly practice thanks to the Mindful Life Project, a local organization that brings meditation, yoga and mindfulness training to the classroom.

Although many schools around the country have implemented similar curriculums, the Richmond nonprofit says theirs is the largest such effort in the country, serving nearly 7,000 students at 15 schools in the district. Mindfulness — defined as the practice of maintaining a nonjudgmental state of heightened or complete awareness of one”s thoughts, emotions or experiences in the present moment — has gained a widespread following in recent years.

“Classrooms are often full of chaos, especially in schools that focus more on academics than social-emotional learning,” said JG Larochette, 35, a former elementary schoolteacher in the district who founded Mindful Life in 2012. “Kids that have experienced a lot of intergenerational violence in their homes or communities or suffered abuse need to have a foundation of social and emotional learning to be available to learn instead of relying on just the fight, flight or freeze instinct.”

Larochette formed the nonprofit after witnessing firsthand the difficulty his students had engaging in class. Children would often act out to be noticed, be belligerent or pick on others, creating a frenetic class environment. Often, they were punished for it, branding them as “the bad kids” and resulting in lost class time, Larochette said.

“When I was teaching, it was really evident that some kids, especially African-American boys, were being pushed further and further away from the education system through suspensions or detention,” he said.

The West Contra Costa school district has a higher rate of suspensions than state and county averages, with 6.6 percent of students suspended in 2013-2014, the most recent school year for which data is available. By contrast, 5.1 percent of students in Contra Costa County were suspended that year and 4.1 percent throughout the state, according to the California Education Department.

The Mindful Life Project is meant to teach K-8 students to check in with their emotions and properly express them, be fully present instead of dwelling on the past and be less judgmental of themselves and others.

“It works because children feel they have someone to listen to them and they have the space to sort through their feelings,” said Peppina Liano, CEO at Richmond College Prep. “It teaches them how to focus by asking, ”Where are we now? Here.” We have felt the repercussions in our classrooms.”

Liano said the workshops don”t cut into instruction time but are done when students would otherwise be reading. For children who need more one-on-one attention, Mindful Life offers “Rise-Up,” an intervention program that pulls students out of class for 50 minutes for mindfulness instruction that is interwoven with yoga and performing and expressive arts.

According to Mindful Life Project, its work has reduced the number of minutes teachers spend on behavioral issues and drastically lowered suspensions. But some educators say it”s too simplistic to say mindfulness can lead to a drastic drop in suspensions, which often require anger management, therapy and other behavioral interventions.

“It”s been a key component to helping support our students, but it”s not a cure-all for the suspension issue,” said Kim Moses, principal at Stege Elementary in south Richmond, where 97 percent of students qualify for free or reduced-price lunch.

Meanwhile, Mindful Life Project is pushing into two schools in the Oakland Unified School District early next year and has recently unveiled a new app students and their families can use for daily practice. It”s also hosting a Nov. 20 benefit concert at Richmond”s Craneway Pavilion with music, hip-hop performances, food, yoga and “mindfulness” rooms (more information is available at mindfullifeproject.org).